Apparatus for treating liquids with electrical discharges



Feb. 3, 1942. F, HARTMAN 2,271,895

APPARATUS FOR TREATING LIQUIDS WITH ELECTRICAL DISCHARGES Filed July 22, 1936 3 Sheets-Sheet l FIGUSLL 2 l6 v 22 PLAN VlE-U l 26 I q z! 25 22' 4 Z5 IE) IS l4- 1s lo 27 I Q I I u Pl-lMAP-Y i l" i be i 27 INVLNTOLJ Feb. 3, 1942. F. E. I- IARTMAN 2,271,895

APPARATUS FOR TREATING LIQUIDS WITH ELECTRICAL DISCHARGES Filed July 22, 1936 3 Sheets-Sheet 2 lNVLNTOL Feb. 3, 1942. F. E. HARTMAN 2,271,895

APPARATUS FOR TREATING LIQUIDS WITH ELECTRICAL DISCHARGES Filed July 22, 1936 I5 Sheets-Sheet 3 Fatented Feb. 3, i942 ELEQTRICAL DISC G S Frank E. Hartman, Highland Park, Iii, assignor to George H. Bern Application July 22, 1936, denial No. 91,935

(Cl. 204-3M) i Glairns.

apparatus which .permits of a protracted single treatment of a liquid. Another object is the provision of means for artificially cooling the dielectric. A further object is the provision of means for recirculating the gas employed to react with the liquid, together with means for conditioning the gas thus recirculated, for the purpose of increasing the effectiveness of the action of the gas on the liquid.

A still further object is the provision of positive control means for cutting off the electricity to the apparatus, in the event of rupture in the dielectric. Other highly important objects are means for controlling the thickness, uniformity and homogeneity of the film of liquid to be treated. Other objects, advantages and novel features will become obvious to those skilled in the art as these specifications proceed.

Before passing on to a description of the apparatus, methods and improvements comprehended by this invention. it may be well to deal briefly with some of the practical advantages which they offer. No. 705,202, which issued as United States Letters Patent No. 2,089,793, glass coated steel was specified for use as combined dielectric and electrode. This is desirable, both for convenience and durability where the potential difference between the electrodes is relatively low (ca. 4,000 to,5,000 volts) and the energy density is correspondingly low. However, when higher potential differences are employed with accompanying higher energy densities, or high frequency is employed, which yields higher energy densities without the need of so great a potential, pin holes tend to show up in the glass coating, which, on continued operation, soon burn through, exposing the bare metal beneath, a condition which is to be avoided- In the present invention solid glass dielectrics are specified, and dielectric coverage is confined to only one of the electrodes of the apparatus, since any thickness desired may be obtained in a solid glass dielectric.

In my copending application, Ser.

In carrying out a treatment with the apparatus of this invention very thin films of liquid are presented to the discharge, of the thickness of from one to two millimetres. It becomes obvious then, if this film is also to act as the dielectric of the circuit, that it must be both uniform and homogeneous. By homogeneity is meant freedom from physically entrained gas; uniformity refers to cross section. This invention provides very special means for obtaining these ends, as will be presently seen from the description of the apparatus. It may be added, however, that in obtaining uniformity and homogeneity, the initial formation of the film, before it passes under the infiuence of the discharge, is of paramount importance. Contrary to opinion, the action of the discharge on the liquid surface is that of maintaining the uniformity of the film. Film rupture rarely initiates in the zone of the discharge, this inevitably occurs prior to passage of the film under the discharge area, hence the utmost importance of the initial formation of the film.

It is also interesting to point out that the presence of the film on the electrode surface ofiers complete protection to the electrode from etching. When a brush or corona discharge impinges against bare metal, even so hard 9. metal as steel, the surface becomes roughened with time.

For a surface on which it is desired to form and maintain a thin film of liquid, such condition would be a decided handicap. However, even with so soft a metal as aluminum, very prolonged action of the discharge on a film of water no more than one to two millimetres thick, failed to noticeably afiect the original mirror polish of the metal; whereas, no more than one half hours action on the bare metal produced a roughening which gave the metal a. satiny finish. With water, aluminum is affected chemically, in time; the ozone in solution attacking it to form aluminum oxide. Stainless steel has not been noticeably effected, even with water, over the period of my experiments.

It has been found that pre-saturation of the liquid with the gas it is to react with greatly increases the amount of action between them. It has further been found that maintaining the gas phase inactive motion is a further advantage,

I but this is probably tied up with some effect resulting from washing the gas repeatedly with the liquid to be treated. Provisions are made in the present invention for recirculating the gas, through injector action," utilizing the flow of the liquid to be treated for both saturating the liquid with the gas and maintaining the gas in active motion through the discharge area.

It is thought that the action of the apparatus is two-fold: action resulting, on one hand, through theformation of ozone, when oxygen is contained in the gas, and, on the other hand, there is a more direct action due to the migrating electrons, causing an activation of, perhaps, both of the liquid and gaseous phases, with the formation of ionized and excited molecules, and also, perhaps, the rupture oi valency bonds direct-all of which would not properly involve passage of the gas through the ozone state.

In some cases ozone formation alone is the prime object. This is exemplified in the formation of ozonides with the fatty oils. It is further exemplified in the treatment of a "carrier liquid, when ultimate chemical action is to be accomplished outside of the apparatus. For instance, very dilute solutions of ozone in water bleach both animal and vegetable fibers rapidly, and require much less "excess oiwgen" for the same rate and degree of bleaching than is required when chlorine is used to produce the oxygen for the bleach; or even when hydrogen peroxide is employed, or hydrogen peroxide producing agents, such as sodium peroxide, furnish the active oxygen for the bleach. Such being the case the apparatus of this invention may be employed to produce bleaching liquors of high activity. Whilst such liquors are not stable over a long period of time, they may be produced as used, with excellent results and great economy.

For this purpose water may be used as the inert, ozone carrying liquid and it then becomes the object to produce as high a concentration of ozone as possible, in contactwith the water film'within the apparatus, since the amount of ozone that will enter solution in the water is governed by the'partial pressure of the ozone in the gas in contact with it. Active oxygen, which would enter into reaction with oxidizable substances of the liquid film, whilst highly desirable when oxidation in situ is the object, is of little importance here, hence every effort is made 'to increase the ozone production of the discharge.

Now it is found that when oxygen supplied to a discharge, with the view of producing ozone, contains some ozone, there is a tendency for the concentration of ozone thus produced to be lower than when the supplied gas is totally free from ozone. In the apparatus of this invention the repeated washing of the gas with the liquid to be treated is important as contributory to the utilization of.all the ozone formed, as well as maintaining the highest possible ozone production. During the washing operation the ozone contained in the residual gas is taken up by the liquid through chemical reaction therewith. But this is true only when there are reaction possibilities between the liquid and the ozone. Water will not react chemically with ozone, it simply dissolves it, and it will never dissolve all of the ozone, due to the equilibrium obtaining between gases in solution and the atmosphere in contact with the liquid. Thus, when water is the liquid, there always remains some traces of ozone in the gas, after washing with water. Presence of these traces of ozone causes a significant decrease in the ozone produced by the discharge. To overcome this the'recirculated gas is conditioned by passing it through a decomposer, which destroys the remaining ozone content, thus maintaining conditions for the production ofthe maximum only traces of ozone are present, the surface display neither efiect alone being suihcient to adsorb the ozone. With higher concentrations, adsorbents, such as the carbons, silica and aluminum gels, etc, serve the purpose very well indeed. For higher concentrations I have found that catalytic decomposition of the ozone is best resorted to. Such agents offer a greater convenience, since they "saturation nor fatigue. Manganese dioxide, either more-or-less pure, or in the form of minerals of high manganese dioxide content, such as pyrolusite or the amorphous psilomelane, serves to catalytically destroy the ozone very effectively. It is preferably employed in granular form, placed in a bed, after the well known fashion of employing gas ad- 'sorbents.

The electrical characteristics of the apparatus are unusual, when considered with the more general applications of electricity to industrial usage. On inspection of the circuit, as illustrated in Figure 3, it is obvious that the apparatus, or activator proper, is nothing more than a leaky condenser. Major electric damage occurs only on rupture of the dielectric. Now dielectrics rupture in a variety of ways. When only a minor pin hole, or slight crack occurs in a dielectric, although conditions of what might be called a short-circuit obtain, in most cases the actual current, occasioned by this so-called short-circuit, assumes a value lower than that of the normal operating current. On formation of a short circuit, in the usual way, the current rises to a very high value. Through this pin hole, or slight crack, a localized sparking discharge occurs, with a total disappearance of the over-all corona discharge, which obtains when the apparatus is operating properly. Naturally, under such conditions, the liquid is not receiving the proper treatment. Further, if this condition is allowed to endure the slight rupture develops into a large one, giving rise to an arcing discharge, the heat of which is destructive of both product and apparatus. When the dielectric is the enclosing cylinder, a rupture, if allowed to become large, would admit the outside atmosphere, which, in some cases, may cause an explosion. From these remarks it is seen that it is important to deenergize the apparatus immediately upon rupture of the dielectric. fuses, in the ordinary way, offer no protection. Attempts have been made to employ constant current relays for handling this condition, but they are unsatisfactory, since it is frequently desirable to purposelyreduce the current of the circuit. Matters go beyond this, however, for

one can not always be sure of what direction the change in current may take, on dielectric rupture. If the initial rupture is large the rupture I current may be greater than normal, hence protection actuated by current change is very limiting in the commercial practice of the apparatus.

There is, however, in all cases, a decided change, always of the same character, in the spectral characteristics of the luminosity within the apparatus, on rupture of a dielectric, regardless of magnitude of the rupture. Sheer intensity of light, measured in lumens, at any fixed point within the apparatus cannot be counted on, since a small rupture, remotely located with It is also seen that electric respect to the fixed point, may give an even lower lumen intensity than the properly operating discharge. On the other hand, even a very small rupture in the immediate proximity of the fixed point will give a decided increase in lumens at the point. Any large rupture, regardless of location, will increase the lumens falling on any point within the activator. when the discharge is properly operating its spectrum is characteristically blue-to violet, extending, of course-into the ultra-violet. There is very little green light, practically no yellow, an ill defined orange and a very low intensity red. When the dielectric is ruptured, and a metal to metal discharge occurs. which is of the nature of a sparking discharge. thalight in the red region becomes very much intensified, well defined orange and yellow appear, with a good intensity in the green. The spectrum thus becomes preponderdantly green to red. If the rupture is large a hot arc occurs, which, while containing a great deal of blue to violet light is, never-the-less, exceeding rich. in red. The distinguishing difference then, between the several types of discharge is: low intensity from green to red with the corona discharge and high intensity in this region with either the sparking or arcing discharge.

It is seen, therefore, that a photo-electric cell, sensitive to the red end of the spectrum, -may be eifectively employed to operate a relay, immediately upon the formation of an improper discharge, and this, in turn, employed to disconnect the apparatus from the source of power. A cell, highly sensitive from yellow to red, will operate, on even a very small rupture, almost before the entire corona discharge disappears and long before any damage may occur. Cracks in a glass dielectric, which still retain gas pressure without showing a lowering of the operating gage, may be detected and repaired before a cleancut sparking through occurs; This is of highest importance when a liquid film is employed as the dielectric, since the rupture of the film is detected and the power shut oiT before any appreciable quantity of untreated liquid can pass through.

Having set forth the objects of the invention and dealt, in some detail, with the practical value of such objects, it is now proposed to d scribe how the desired objects are achieved. Several embodiments of my invention are illustrated by the attached figures, of which:

Figure 1 represents a cross section of one form J,fil'l, along the line AA of Figure 4 Figure fi represents a sectional view, in elevation, along the line B-B oiFigure 4 Figure 7 represents a plan view, in section,

along the line (3-0 of Figure 4.

Like numerals designate like'parts throughout the several figures and the description thereof.

Referring to- Figure 1, the activator proper is designated generally as i. It comprises a base section 2, provided with an inlet tube 3 and an outlet tube 1, same either forming or terminating To the base section is secured the centre tube,

or electrode 8, the counter bore receiving same being enlarged over a portion of its depth to .provide the well 8, for receiving the liquid which flows down the outer wall of 9. The base section 2 is also bored, as at 4, to receive the outer, or dielectric, tube 25.. A gasket 5 is provided between 28 and 2 for rendering their junction both gas and liquid tight.

Theicentre tube, or electrode, 9 is provided with a head casting ill, same being closed at the bottom. as indicated at H, excepting for a small opening into which the upright tube I2 is secured. Tube It extends upward to a distance slightly beyond the plane occupied by the apertures I5 and I5. Head ill is preferably of the shape shown, being provided with the radius I 8' for the dual function of assisting in the formation of the liquid film which flows down the outer wall of 9, and the prevention of edge effects, or intensified discharges, which tend to form when the end of an electrode terminates with a sharp edge. The top Iii is closed with the plug it, which carries the baiiie tube it, which extends downward into the head, sumciently to leave only an adequate passageway for the liquid between the lower end of it and the closure H. Plug it also contains an opening into which is fitted the gas escapement tube 28, same being closed at its top and provided, in the wall, with a series of apertures M.

A cap member I8 is provided for closing the top of the activator proper, same being bored to receive the gasket 28 against which 25 is secured to make a gas tight seal. Cap member It also carries the stufling box l1, into which is threaded the packing gland I 8, to operate against the packing l9, thus providing a gas tight seal for the film control shaft 20. Shaft 20 is hollow, but closed at its upper end and is threaded internally to receive the upward extending and threaded portion of .23, about which 20 may be revolved by turning the knob 20', thus raising and lowering it on 23.

At the lower end of 20 the film control skirt is.secured. This comprises the plug 22, which is secured to 20 and further carries the tube 21, which is the film control skirt proper. Plug 22 is provided with a series of apertures 22' for connecting the interior of tube 2| with the interior of the activator proper.

The dielectric tube 25, which is of glass or other suitable dielectric material, is provided, over a portion of its outer surface, with a closely adhering metallic film 21, said film being confined to the medial portion of- 25, terminating sufficiently back from both-ends to provide ample electrical insulation between 21 and the remaining metallic parts of the apparatus.

The activator is secured together with the tie rods 50, which may be covered with insulating tubes 5|, to prevent sparking between the rods and 21, without the necessity of spacing the rods too remotely from 21. a

A gas outlet tube 28 is provided in the wall of 25, and connects with an enlarged tube 29, which serves as a connecting chamber between the interior of the activator proper and certain auxiliary apparatus. The bottom of 29 is provided with a downward extending tube 30, which dips into a trap tube 3|. Trap 3| is provided with an outlet 32 which may be connected with any suitable receiver orreservoir. This trap functions to prevent accidental overflow from the activator entering the lines leading to either the injector or the decomposer.

A tube 33 is taken from 29 and leads, through the stop cock 35, to the bottom of the decom= poser 4!, as indicated at 31. A further tube 84 is taken from 29 and leads, through stop cock 88, to the gas inlet port of the injector 48. It is obvious that one three way valve may be used to replace these stop cocks; however, single cocks have been used to make the drawing more clear. A tap 46 is taken from tube 34, as indicated at 48, and leads through the stop cock 45, to the top of the decomposer 4|, as indicated at 43. Tube 44 is further provided with'a tap 52, which leads through the shut-oil pack 53 to a source of gas or gases.

The figure illustrates only one source of gas, 55. However, a mixture of gases may be employed, in which case any suitable means for providing the activator with-mixed gases may be employed. Gas is admitted to the activator, preferably through a pressure control valve, as indicated by 54, as it is important to maintain a constant supply of gas to the activator, under some constant and predetermined pressure.

The decomposer 4| consists of a chamber 38, provided with an inlet 31. Located at the bottom of the chamber is a screen 39, permeable to gas but of such mesh as to retain the material 40, which fills the body of the chamber. A removable top section 42 is provided, carrying the outlet port 43. The material 40 which fills the chamber may be any suitable adsorbent or catalytic material, as has already been discussed.

The base 2 of the activator is electrically con nected with earth, and any suitable source of high tension electric current, at any suitable frequency, when alternating current is employed, may be used to energize the activator, such, for example, as furnished by the transformer 56. One side of the high tension is connected with the base 2, and, in consequence, earthed, and the other side is connected to electrode 21, as indicated at 51 and 58 respectively. The transformer 56 may have its primary energized from any suitable source of electric power.

this must be done through a suitable insulator. Such an insulator is designated generally as59. A skirt 59 may be secured with a gasket and bolts, not shown, to provide an air tight connection between the insulator and the tube 63. Inserted into the insulator and sealed therein, is the metallic stud 80. To this stud the high tension lead 85 is connected as indicated at 58. A spring 6| co-operates with the stud 60 and the metallic rod 52, the rod having at its inner end an enlarged portion or plate 81, which is held in pressure contact with 21, by the action of 6|, and thus good electric contact is ensured for 21, and insulated from the remaining metallic parts of the apparatus,

The gas outlet tube 28, secured to of Figure 1, is, in this case, removed from the dielectrio and provided in the base casting, as indicated by 28, the base casting being sufllciently elongated to provide proper depth of the well 6.

Figure 3 also illustrates a means for protecting the apparatus against damage from dielectric rupture. A photoelectric cell, sensitive to the red end of the spectrum, and relatively insensitive to the blue-violet end, is made in annular construction and positioned at the top of the an- In Figure 1 the dielectric tube 25 serves also to enclose the activator against the atmosphere. For this reason it is essential that it be secured tightly between 2 and Hi. When the dielectric is of large diameter, and relatively high gas pressures are employed, the clamping essential to effective sealing, places a considerable mechanical strain on the dielectric, which is not desirable, since it predisposes the dielectric to rupture under electrical stress. For large apparatus, therefore, it is desirable to relieve the dielectric of mechanical strain and provide a separate tube for enclosing the activator. Figure 3 illustrates one way of accomplishing this. Note that here, 25 is free from any clamping action. It is'positioned and centered by the bottom centering ring 19, a similar ring, I8, serving a similar purpose at the top. The dielectric slips snugly but freely into these rings. A metallic tube 63 is provided forenclosing the activator. Grooves I1 and H are provided in the top and bottom sections respectively, for receiving 63, and a gasket, not shown, may be provided for ensuring a tight seal. The activator is again secured together by suitable tie rods as illustrated by Fig. 1.

It is necessary, however, to convey the high tension lead to 21, and as 63 is earthed, along with the remaining metallic parts of th apparatus,

nulus formed by 9 and 25, as indicated at 64. From this positionthe cell scans the entire depth of the discharge annulus 'and any luminosity'within same will impinge on the active surface of the cell. A stufling box 65 is provided in Hi to admit passage for the cell leads 66 and 56'. These leads are brought out and connected with an amplifying unit 61, the output from the amplifier being conducted through leads 68 and 68' to the relay 69.

The contacts Illnof relay 69, are in series with the solenoid circuit of the main contactor H, hence when the relay functions, the electric sup- Ply to the activator is cut off. Since contactor H is controlled by a three wire circuit, or novoltage-release, electric supply cannot be reestablished to the activator until same is purposely done by hand. This necessitates the pushing 01 the start button 82, of control switch 14. The forces which cause cell 64 to function to offer the desired protection have previously been described.

The main electric circuit of the apparatus is as follows: Power, at low tension, from any suitable source, is conveyed through L1 and L: to the service studs of contactor I I. From the load side of the contactor the leads l5 and 15' conduct power to the primary of the transformer 56. In

one lead, as in 15, a reactance or choke coil 16 is connected in series, said coil may have a movable core, or otherwise the iron may be adjusted,

. and thus the coil be made to control the current in the circuit, thus controlling the energy in the activator. A reactance is more desirable for this purpose than a resistance, such as is offered by a rheostat, since it is more sharply current limiting, especially at high frequencies, and further aids in tuning the over-all circuit. The action of the activator, being that of a condenser, introduces a considerable capacity reactance into the circuit. The inductive reactance of the transformer, even when same is of the high reactance type, is rarely sufiicient to yield a good power factor for the operation of the activator. The use of further inductance is therefore indicated. A further aid to tuning, when high frequency is employed, is the spacing of the high frequency leads. Due to the magnitude of the mutual reactance of parallel leads at the higher button a: is connected directly with is." The stop button 83 is connected in series with the contacts of the cell relay 59 and thence to one side noid is connected directly to L1. An extra contact is provided on H and short-circuited on the load side to La and the service side of this contact is connected with the common connection 84 of switch I4. This constitutes a hold-in tip necessary to the three wire, momentary contact" control of the contactor, which is required in order to render the functioning of the cell 04 effective for complete shutdown. It suchcontrol was not employed, when the circuit was first broken by the cell the actuating light would be extinguished and the cell would no longer feed current to relay 69 and the contacts of- ,10 would again close. In the absence of momentary control of II, this would produce a condition of chattering, with repeated cutting off and on of the activator. However, with the control as shown, once the control circuit has been broken it can only be re-established by hand.

Figure 4 illustrates what may be termed flat plate construction, as opposed to the tubular construction of Figures 1 and 3. This comprises of the solenoid I2. The opposite side of the solechamber I20, which is conveniently constructed of metal, comprises a bottom I2I, side walls I20, a ledge I26" being provided in the side walls for supporting the plate dielectric I23. Dielectric I23 also serves to close the top of the discharge chamber I20, and may be luted into place, or

3 otherwise secured to make a gas tightseal. This construction is. clearly shown in the transverse section, Figure 5. r

The wall IOI' is slotted, as at II2, for connecting the interior of I00 with the interior of I20. This slot does not extend the full width of IN but is made only suiliciently long to fall within the space described by the dim inserts I22, as shown in Figure 5. This slot is covered with a sliding door I I4, which is secured in sliding relation with the wall IIIP by the guides I". D001 a saturating column, designated generally as 00.

This column is provided with an enlarged top section I00, which is closed with the removable top 98, secured by the bolts 09, and a gasket, not

shown, may be provided for rendering the top as tight. 1

Top 98 is provided with the stufllng box 31, through which the tail pipe 05 of the injector 48 is introduced. A packing gland 83 screws into this stufling box and compresses the packing 96' 4 to seal the passage of the tail pipe. Pipe 95 extends downward into the saturating column to within a short distance of the bottom. Column 88 is provided with a partition 00, containing an opening into which the upright tube 3| is fitted. Tube 9| is provided with a series of apertures 9i" as shown. A ring 94 is pressed on the top ofll, serving to close the top of the annulus formed by tubes 9| and 03. A baflle tube 03 is pressed onto 94 and extends downward to within a short distance of the partition 00. The wall of 83 is provided with a series of apertures 32 as shown. This assembly of tubes constitutes a gas separating device, the operation or which is later described.

The enlarged top section I00 is provided with a downward extending pipe "II, which dips into a trap or liquid seal I03, same having an outlet I03, which may be connected with any suitable receiver. The tube I02 is slip-fitted inside oi I0 I and is provided with an interior web I03 to which is secured the rod I04, same being threaded near its top and passes outwards through 08. Stufling box I05 is provided as a passageway for the rod, the packing gland I00 and packing I00 serves to render the passageway gas tight. A nut I01 screws onto the extending portion of I04 and may be manipulated to raise and lower I02 in IN and secure I02 in position.

At one side of section I00 the discharge chamber, designated generally as I20, is attached and secured to I00 by the flange I2I'. Discharge lid is provided with a boss 3 to which is accured the rod I I5, same serving to raise and lower H0 across the slot II2. Rod IIB passes out through 08, the stufiing box IIB being provided for this purpose and into which the gland III is screwed to compress the packing III and thus render the passageway gas tight. Nut I I3 is provided for the manipulation of IN and securing same in place. As only liquid must pass through slot H2 and as a gas must also be supplied from I00 to I20, tube H9 is provided for making the gas connection between them.

The lower end of I20 is provided with a downward extending throat I3I. A ledge I is provided in the discharge chamber I20 for supporting the dielectric plate I23, and to which it may be luted or sealed. A boss I23 is provided on the end wall I26, the opening, I27, in this boss, receiving pipe I28, which connects the trough formed by the walls I26-I23' and the dielectric I23, with the similar trough formed in the lower, attached discharge chamber I20. An opening I25 is provided in walls I26, at both sides, as shown, and a perforated pipe I39 connects these openings, bosses I26 being provided on the exterior of the walls for receiving externally connected pipes which supply cooling liquid to perforated pipe I33.

To the flange I3I' a second discharge chamber I20 is secured by the companion flange I32. At the upper end of this chamber a well section I33 is provided, said section being continuous with a discharge chamber substantially identical with I20. It consists of a bottom I2I', side walls I26' and end wall I44. A ledge is provided In walls I20' to support the dielectric plate I23, and film inserts I22 are provided in I2I', all similar to chamber I20. The lower end of this discharge ,chamber is provided with a well section I42, covered, in part, by the top wall I43, which is cut back to form the bottom support of I23, as'shown. A boss I44 is provided in wall I42 and to which is secured the U-trap liquid outlet tube I30. In wall I43 a gas outlet tube I36 is provided.

In the throat section I33 one wall is provided 2 with an inverted -v-shaped boss I38, as shown,

Operation of apparatus Figure 1 The operation of the activator is as follows:

i The liquid to be treated is introduced through the liquid inlet 49 of the injector 48, under sufficient pressure to force the liquid through the injector tail pipe 56 and elevate it within 9 to the point of overflow through the apertures i5, 01

head I 9 and further entrain gas against the head of liquid in 9 and compress it against such internal gas pressure as the acti'vator may be operated under. 7

The liquid thus introduced flows out of the head [0, through the apertures l5, filling the annulus formed by ID and 2|. Skirt 2| is elevated sufiiciently to permit the liquid to pass out about its periphery and in so doing it runs as a thin film down the wall of 9. The film control skirt 2| serves to evenly distribute the liquid about the periphery of the radius 10', so that a film of uniform thickness is maintained on the outer wall of 9. It further serves to quickly establish a uniform film on starting up.' There is a tendency with liquids which do not readily wet surfaces to run in rivulets along 9. When this occurs, 2| is lowered to shut off the fiow of liquid and then quickly raised, an increased flow of liquid, evenly distributed about I9 is established, and by repeating this operation, if necessary, an even film on 9 is readily established.

In maintaining the uniform feed of liquid about 59' it'is important that no gas bubbles accompany the liquid. Since the film to be maintained is exceedingly thin, upwards of a millimetre, the presence of bubbles tends to break the film. In order to ensure against this contingency all physically entrained gas is separated from the liquid before it passes out of apertures 15.

The stream in pipe 53 contains gas and liquid finely dispersed as exceedingly small bubbles and globules. Due to the high velocity of this stream very little coalesence of the gas occurs. It is here that good saturation of the gas with the liquid is obtained. When this stream discharges into 9 the velocity is greatly reduced and the gas tends to separate almost at once. By the time the stream approaches the top of 9 the gas has condensed into a stream of rather coarse bubbles, and in this condition both gas and liquid pass through tube 12. Here, however, the velocity is again increased, but thegas, having already condensed will not again become finely dispersed throughout the liquid, since the original dispersion is characteristic of the action of the injector employed.

The gas escapment tube 23 is positioned immediately over [2, thus, the gas leaving l2 passes rapidly out through 23, via the apertures 24, and finally enters the activator proper, first passing through the apertures 22' of the film control plug. The liquid, however,- afterleaving l2, must pass again downward through the annulus l2|4, to pass upwards, in turn, through the annulus l9l4. This reversal of the fiow of the liquid ensures the disengagement of all bubbles during its downward course, this being sufficiently slow to prevent the gas following the liquid.

The gas fiitroduced with the liquid fills the activator and surrounds the film of liquid fiowing down the outer wall of 9. The liquid film from 9 collects in the well 6, but cannot flow out of the activator until its head is sumcient to overcome the trapped outlet 1. When the head reaches the height determined by 8, which is preferably slightly below the gas outlet 28, the liquid may then flow from the activator into any suitable reservoir or receiver.

The gas which follows the liquid film cannot escape through 1, due. to the trapping arrangement. The gas pressure at which the activator is operated is determined by the height of the column of liquid in l, which may be anything desirable within reason, It should be pointed out that should higher gas pressures be desirable, than can be obtained conveniently with a liquid trap, any suitable type ofpressure valve or escapement valve may be employed in place of the trap shown. The gas leaves the activator through the gas outlet 28, and may be either directly recirculated, or recirculated through the decomposer, as conditions may demand.

If it is desired to directly recirculate the gas, cocks and 95 are closed and cook 36 opened.

The gas then passes out of the activator through is continuously fed into the system from reservoir .55 to replace that used up. A pressure regulating valve 54 is employed for the introduction of the gas, and this is set to just deliver gas against the head occasioned by the traps I and 3!, thus maintaining the gas volume of the activator under a constant and predetermined pressure.

If it is desired to recirculate the gas through the decomposer, cocks 35 and 45 are opened and cock 36 is closed. In this case gas leaves the activator at 28, passes through 29, enters 33, en route to the bottom of the decomposer at 31, upwards through the decomposer, out through 43, cook 45, tube 44 and enters the gas tube 4! of the injector '48. Deficiencies in gas volume are made up in precisely the same way as previously described. v

The activator may be energized with electricity through any suitable switching arrangement, such as contactor II, when the photo-electric cell control of the apparatus is employed. The photo-electric cell control should properly be considered in the operation of the device, but since this has elsewhere been described in detail it will not be repeated here. When the transformer is energized, a potential difierence is established between the outer electrode 21, on the outer wall of dielectric 25 and the inner electrode or tube 9. .When the potential difference is suflicient, a brush, corona, or so-called silent electric discharge occurs throughout the entire area described by electrode 21, filling the annulus formed by 25 and 9. When the liquid film is flowing down 9 the discharge impinges on the film, thus obtaining intimate contact between gas, liquid and discharge.

vOperation of the activator under somewhat elevated gas pressure ofiers several advantages. In the first place it increases the chemical efiiciency, since there are more gas molecules to become activated for the same flow of energy. In addition to this, elevated pressures appear to stabilize the discharge and discourage any Operation of apparatus, Figure 4 Essentially the operation of the plate construction apparatus, illustrated in Figures 4, 5, 6 and "l, is the same as that just described for the tubular construction.-

The liquid to be treated is introduced through tendency for the-film to spread. The spreading film being exceedingly thin, the passage of the gas from the throat into the second discharge the liquid inlet of the injector 48. Here gas is drawn into the liquid, and the mixture delivered to 88 through 05. This mixture passes upward in 30, the gas quickly condensing into large bubbles; Gas and liquid pass through themnulus formed by 95 and BI. When the liquid reaches the apertures 9| it passes outwards through same and fiows down through the annulus formed by 9i and 93. The gas, however, continues upwards and ultimately out at the top of M and into I00.

After the liquid has filled the annulus 9I-93. below the apertures 0|, it flows upward again through the annulus 93-09, ultimately reaching I00. This tortuous gas separating trap is required only when the liquid is viscous and tends to hold entrained bubbles. If completeseparation of the gas does not occur in 9I-95, it will continue to separate in 9I,-93, and such gas as there separates passes into I00 through apertures 92. When a non-viscous liquid is treated, gas separation is more easily accomplished. In this case the wall 80 'may be extended upward into I00, as indicated by the broken lines 39' and as this delivers the gas-liquid mixture above the level of the liquid in I00, adequate gas-liquid separation is obtained, so that-nogas passes out through H2.

The liquid entering I00 must pass out through slot II), and thus enter the discharge chamber 1 I20. Door H4 is adjusted to give the required film thickness, then the rate of liquid supply to the apparatus is maintained so that there is always a slight head acting to cause flow through II2. This will maintain a film flow of uniform thickness at all times. If the liquid is reluctant to wet the entire width of the film passage way on I2I, slowly lowering II4 quickly raising it will greatly aid in obtainingra uniform initial wetting.

To aid in maintaining the head constant, the tube I02 may be adjusted at the required level and the rate of supply made just a little greater than is required. A slight excess is then bled out through I02 and trap I08, from whence it may be collected and returned to the main reservoir. This further compensates for minor variations in flow, as will frequently occur with pumps, etc. I

The accompanying gas passes from I00 into I20 through tube II9, and thus follows the course of the liquid film, precisely as with the tubular construction. Gas tubes I36 and I31 may be connected with the remaining external apparatus of the gas circulating system, precisely as illustrated in Figure 1. Tube I36 connects with 20 and I3! with 34 of Figure 1.

When the liquid film reaches the bottom of I 20 it passes downward through the throat I3I, accompanied by the superimposed layer of gas. Although the liquid film does not cover the entire width of I2I, being confined to the path described by guides I22 of Figure 5, there is a chamber tends to blow the film about. An effective way of avoiding this, as well as the tendency for the thin film to hug the top of the casting, is offered by the spreader I38, illustrated in Figure 6, which divides the film into two relatively thick streams, with an open space between them for the passage of the gas. These streams enter the well I34, and thence overflow in a film, downwards along I2I and ultimately into the outlet well I42, out through trap I39 and to any suitable reservoir set to receive it.

The gas also passes over the liquid through the second discharge chamber and re-enters the circulating system through I36. Only two discharge chambers are shown, by way of illustration, but obviously as .many may be employed as is required to give the liquid the proper time of treatment.

The electric discharge takes place from the electrodes I24, I24 to the bottom plates I2I, I2I in precisely the same'way as described for the tubular construction. One decided advantage of the plate construction, apart from the greater facilities for obtaining large plates of glass 'of proper thickness, is that the plate may be sloped at any desired angle, and thus the rate of flow through the discharge area is brought under control. With perpendicular, tubular construction, this is not possible, the rate of fiow down the electrode being governed by gravity and the viscosity of the liquid.

It should be pointed out that electrode I24 does not completely cover theouter surface of dielectric I23, but a margin is left all around. This margin should be of sufiicient width to properly insulate I24 from the metallic parts of the apparatus. It should 'also be noticed that the film inserts or guides, I22, are so located in plate I2I as to confine the boundary of the liquid film to immediately beneath the electrode area, thus all of the flowing liquid is subjected to the discharge. These inserts extend the full length of plate I2 I.

. At the upper end they are so arranged that no liquid can pass down outside of them. For electric reasons the ins rts are best made from insulating material. glass and maple wood serve excellently.

When very high energy densities are employed it may become desirable to liquid cool the dielectric. The cooling liquid is introduced through ports I25 and distributed uniformly across the dielectric by the perforated pipe I39. It then flows downward along the trough formed by walls I23 and the dielectric, through pipe I23, which conveys it to the top of the second discharge chamber. It passes along this chamber and is ultimately discharged from I35. The cooling liquid is preferably a good insulating oil, which may be recirculated through an inter-cooler, employing water for cooling the oil.

A drain is provided at the bottom of the saturating column, as indicated at IIO, through which the column may be drained for any purpose desired.

It should be pointed out that the apparatus and means herein disclosed are by way of illustration only, and must not be construed as limiting the invention in any way. It is obvious that many variations may be employed without departing from the spirit of the invention.

For instance, an injector is shown as a means of circulating the gas. It is obvious that this may be replaced by any suitable gas pump, forcing the gas into the liquid at any suitable point, and under conditions which give a line dispersion, such as a porous cup or body. It is also obvious that gas may be dissolved in the liquid in an entirely separate apparatus, such as a pressure chamber wherein the liquid supplied to the treating chamber is maintained under gas pressure, and, if desired, agitated to facilitate solution of the gas. It is equally obvious that separation of the phyiscally entrained gas may be accomplished in a variety of ways, that films may be otherwise formed, such, for instance, as allowing jets to impinge on the surface. In such manner, together with the manner disclosed, I have produced a film on the outer tube, which, in such case was a bare metal electrode, whilst the inner electrode was covered by the dielectric.

It should also be pointed out that the liquid supply to the treating chamber may be controlled through a solenoid valve, or other electric control means, and thus, when the photo-electric cell functions to cut off the current from'the apparatus it also serves to arrest the, flow of liquid. Numerous adaptations and variations are possible with the elements of this invention, and what I wish to secure to myself by Letters Patent is given by the appended claims.

I claim:

1. In an apparatus having a chamber for treating liquids with electric discharges in the presence of gas, means to presaturate the liquid with gas before subjecting it to electric discharge, means for liberating the excess gas from the liquid previous to subjecting the liquid to electric discharge, means to pass the liquid to be treated in a thin film through the treating chamber, means to cause a positive flow of gas through said chamber and means for passing an electric discharge through said treating chamber.

,2. In a liquid treating apparatus, a treating chamber, meansfor passing the liquid under treatment through said chamber in thin films, means for subjecting the liquid to electric discharge while passing through said chamber,

means to introduce a gas into said liquid prior to the entry of the liquid into said chamber, whereby to pre-saturate the liquid with the gas, a gas and liquid separation chamber between said pre-saturation means and the treating chamber, separate gas and liquid outlet connections from the separation chamber to the treating chamber, and suction means for drawing the free gas from said treating chamber.

3. In a liquid treating apparatus, a treating chamber, means for passing the liquid under treatment through said chamber in thin films, means for subjecting the liquid to electric discharge while passing through said chamber, means to introduce a gas into said liquid prior to the entry of the liquid into said chamber, whereby to pre-saturate the liquid with the gas, a gas and liquid separation chamber between said pre-saturation means and the treating chamber, separate gas and liquid outlet connections from the separation chamber to the treating chamber, and suction means for drawing the free gas from said treating chamber, said suction means comprising an injector actuated by the incoming liquid.

4. In an apparatus having a chamber with an inlet and an outlet for treating liquids with electric discharges in the presence of gas, means for passing an electric discharge through said treating chamber, means to presaturate the liquid with gas before subjecting it to electric discharge, means for liberating the excess gas from the liquid previous to subjecting the liquid to electric.

discharge, means to pass the liquid to be treated in a thin film through the treating chamber and gas recirculating means operatively connected to the inlet and outlet of said treating chamber to cause a positive flow of gas through said chamber, said recirculating means including an ozone decomposing chamber and means to draw the gas from said treating chamber through the decomposing chamber and again deliver it into the liquid to be treated.

FRANK E. HARTMAN. 

